Talk:Landé g-factor

g-factor

According to two of the most standard quantum mechanics textbooks (Griffiths and Merzbacher), as well as most (though not quite all) publications I can find, the term "Landé g-factor" refers specifically to g_J, while the term "g factor" or "g value" refers to the more general case of any dimensionless factor in an equation for a magnetic moment.

Therefore, I wrote the article g factor on the more general topic of g factors, leaving in this article only the information on g_J. I will also put in a note warning that this usage is not quite universal.Steve 01:03, 12 December 2006 (UTC)

A derivation

I added a derivation since I have found the derivation in the ref[1] (http://hyperphysics.phy-astr.gsu.edu/HBASE/quantum/Lande.html) is not good enough (though comes out in the first place when one does google). It tried to define the magnetic moment alone the direction of the external magnetic field (z-axis), and made use of the following expression

${\vec {A}}\cdot {\vec {B}}={\frac {({\vec {A}}\cdot {\vec {C}})({\vec {C}}\cdot {\vec {B}})}{{\vec {C}}\cdot {\vec {C}}}}$

which is not valid even for normal (non-operator) vectors (therefore some explanation is necessary). To me, two approaches are better, one is to rigorous prove it using Wigner-Eckart theorem (by making use of the fact that ${\vec {\mu }}_{J}={\vec {\mu }}_{L}+{\vec {\mu }}_{S}$ is a tensor operator) as done in the textbook of Ashcroft, or one simply believes that the magnetic moment lies on the direction of J and calculate the projections of ${\vec {\mu }}_{L}$ and ${\vec {\mu }}_{S}$ on this direction.

Gamebm (talk) 12:51, 23 November 2012 (UTC)

formulae, images broken - http vs https

When accessing this page using http: (http://en.wikipedia.org/wiki/Land%C3%A9_g-factor) I can't see many of the images including the formulae, but when accessing through https I can. There are some 503 errors when using http (http://upload.wikimedia.org/wikipedia/en/b/bc/Wiki.png [HTTP/1.0 503 Service Unavailable 3ms]) Seems to be a problem with Wikipedia in general. Someone please escalate this as appropriate. — Preceding unsigned comment added by Abhijit86k (talk • contribs) 06:15, 14 October 2014 (UTC)